AMP-activated protein kinase, a metabolic master switch: possible roles in type 2 diabetes

Upregulation of the AMPK-FOXO1-PDK4 pathway is a primary mechanism of pyruvate dehydrogenase activity reduction in tafazzin-deficient cells

Barth syndrome (BTHS) is a rare disorder caused by mutations in the TAFAZZIN gene. Previous studies from both patients and model systems have established metabolic dysregulation as a core component of BTHS pathology. In particular, features such as lactic acidosis, pyruvate dehydrogenase (PDH) deficiency, and aberrant fatty acid and glucose oxidation have been identified. However, the lack of a mechanistic understanding of what causes these conditions in the context of BTHS remains a significant knowledge gap, and this has hindered the development of effective therapeutic strategies for treating the associated metabolic problems. In the current study, we utilized tafazzin-knockout C2C12 mouse myoblasts (TAZ-KO) and cardiac and skeletal muscle tissue from tafazzin-knockout mice to identify an upstream mechanism underlying impaired PDH activity in BTHS. This mechanism centers around robust upregulation of pyruvate dehydrogenase kinase 4 (PDK4), resulting from hyperactivation of AMP-activated protein kinase (AMPK) and subsequent transcriptional upregulation by forkhead box protein O1 (FOXO1). Upregulation of PDK4 in tafazzin-deficient cells causes direct phospho-inhibition of PDH activity accompanied by increased glucose uptake and elevated intracellular glucose concentration. Collectively, our findings provide a novel mechanistic framework whereby impaired tafazzin function ultimately results in robust PDK4 upregulation, leading to impaired PDH activity and likely linked to dysregulated metabolic substrate utilization. This mechanism may underlie previously reported findings of BTHS-associated metabolic dysregulation.

Advances and Challenges in Modeling Cannabidiol Pharmacokinetics and Hepatotoxicity

Cannabidiol (CBD) is a pharmacologically active metabolite of cannabis that is US Food and Drug Administration approved to treat seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex in children aged 1 year and older. During clinical trials, CBD caused dose-dependent hepatocellular toxicity at therapeutic doses. The risk for toxicity was increased in patients taking valproate, another hepatotoxic antiepileptic drug, through an unknown mechanism. With the growing popularity of CBD in the consumer market, an improved understanding of the safety risks associated with CBD is needed to ensure public health. This review details current efforts to describe CBD pharmacokinetics and mechanisms of hepatotoxicity using both pharmacokinetic models and in vitro models of the liver. In addition, current evidence and knowledge gaps related to intracellular mechanisms of CBD-induced hepatotoxicity are described. The authors propose future directions that combine systems-based models with markers of CBD-induced hepatotoxicity to understand how CBD pharmacokinetics may influence the adverse effect profile and risk of liver injury for those taking CBD. SIGNIFICANCE STATEMENT: This review describes current pharmacokinetic modeling approaches to capture the metabolic clearance and safety profile of cannabidiol (CBD). CBD is an increasingly popular natural product and US Food and Drug Administration-approved antiepileptic drug known to cause clinically significant enzyme-mediated drug interactions and hepatotoxicity at therapeutic doses. CBD metabolism, pharmacokinetics, and putative mechanisms of CBD-induced liver injury are summarized from available preclinical data to inform future modeling efforts for understanding CBD toxicity.

Steatotic Liver Disease: Pathophysiology and Emerging Pharmacotherapies

Steatotic liver disease (SLD) displays a dynamic and complex disease phenotype. Consequently, the metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) therapeutic pipeline is expanding rapidly and in multiple directions. In parallel, noninvasive tools for diagnosing and monitoring responses to therapeutic interventions are being studied, and clinically feasible findings are being explored as primary outcomes in interventional trials. The realization that distinct subgroups exist under the umbrella of SLD should guide more precise and personalized treatment recommendations and facilitate advancements in pharmacotherapeutics. This review summarizes recent updates of pathophysiology-based nomenclature and outlines both effective pharmacotherapeutics and those in the pipeline for MASLD/MASH, detailing their mode of action and the current status of phase 2 and 3 clinical trials. Of the extensive arsenal of pharmacotherapeutics in the MASLD/MASH pipeline, several have been rejected, whereas other, mainly monotherapy options, have shown only marginal benefits and are now being tested as part of combination therapies, yet others are still in development as monotherapies. Although the Food and Drug Administration (FDA) has recently approved resmetirom, additional therapeutic approaches in development will ideally target MASH and fibrosis while improving cardiometabolic risk factors. Due to the urgent need for the development of novel therapeutic strategies and the potential availability of safety and tolerability data, repurposing existing and approved drugs is an appealing option. Finally, it is essential to highlight that SLD and, by extension, MASLD should be recognized and approached as a systemic disease affecting multiple organs, with the vigorous implementation of interdisciplinary and coordinated action plans. SIGNIFICANCE STATEMENT: Steatotic liver disease (SLD), including metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, is the most prevalent chronic liver condition, affecting more than one-fourth of the global population. This review aims to provide the most recent information regarding SLD pathophysiology, diagnosis, and management according to the latest advancements in the guidelines and clinical trials. Collectively, it is hoped that the information provided furthers the understanding of the current state of SLD with direct clinical implications and stimulates research initiatives.

Bacoside-A repressed the differentiation and lipid accumulation of 3T3-L1 preadipocytes by modulating the expression of adipogenic genes

Obesity is one of the more complicated diseases, it can induce numerous life-threatening diseases mainly diabetes mellitus, cardiovascular disease, hypertension, and certain cancers. In this study, we assessed the efficacy of bacoside-A (a dammarane-type triterpenoid saponin derived from the plant Bacopa monniera Linn.) on the adipogenesis of 3T3-L1 preadipocytes. Results of this study illustrated that bacoside-A decreased the differentiation of 3T3-L1 cell, as evidenced by diminution of lipid droplets, which contains triglycerides and other lipids. During the differentiation process, transcription factors, which are mainly participating in adipogenesis such us CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPβ, peroxisome proliferator-activated receptor-γ (PPARγ), and sterol regulatory element-binding protein-1c (SREBP-1c), expressions were significantly suppressed by bacoside-A. In addition, bacoside-A showed a potent reduction in genes precise to adipocytes such as lipoprotein lipase (LPL), fatty acid synthase (FAS), adipocyte fatty acid-binding protein (FABP4), and leptin expressions. Further, bacoside-A stimulated the phosphorylation of acetyl CoA carboxylase (ACC) and AMP-activated protein kinase (AMPK). These results demonstrated that bacoside-A has anti-adipogenic effects by regulating the transcription factors involved in adipocyte differentiation. Therefore, bacoside-A might be considered as a potent therapeutic agent for alleviating obesity and hyperlipidemia.

Upregulation of the AMPK-FOXO1-PDK4 pathway is a primary mechanism of pyruvate dehydrogenase activity reduction and leads to increased glucose uptake in tafazzin-deficient cells

Barth syndrome (BTHS) is a rare disorder caused by mutations in the TAFAZZIN gene. Previous studies from both patients and model systems have established metabolic dysregulation as a core component of BTHS pathology. In particular, features such as lactic acidosis, pyruvate dehydrogenase (PDH) deficiency, and aberrant fatty acid and glucose oxidation have been identified. However, the lack of a mechanistic understanding of what causes these conditions in the context of BTHS remains a significant knowledge gap, and this has hindered the development of effective therapeutic strategies for treating the associated metabolic problems. In the current study, we utilized tafazzin-knockout C2C12 mouse myoblasts (TAZ-KO) and cardiac and skeletal muscle tissue from tafazzin-knockout mice to identify an upstream mechanism underlying impaired PDH activity in BTHS. This mechanism centers around robust upregulation of pyruvate dehydrogenase kinase 4 (PDK4), resulting from hyperactivation of AMP-activated protein kinase (AMPK) and subsequent transcriptional upregulation by forkhead box protein O1 (FOXO1). Upregulation of PDK4 in tafazzin-deficient cells causes direct phospho-inhibition of PDH activity accompanied by increased glucose uptake and elevated intracellular glucose concentration. Collectively, our findings provide a novel mechanistic framework whereby impaired tafazzin function ultimately results in robust PDK4 upregulation, leading to impaired PDH activity and likely linked to dysregulated metabolic substrate utilization. This mechanism may underlie previously reported findings of BTHS-associated metabolic dysregulation.

Polphylipoprotein-induced autophagy mechanism with high performance in photodynamic therapy

Polphylipoprotein (PLP) is a recently developed nanoparticle with high biocompatibility and tumor selectivity, and which has demonstrated unprecedentedly high performance photosensitizer in photodynamic therapy (PDT) and photodynamic diagnosis. On the basis of these discoveries, PLP is anticipated to have a very high potential for PDT. However, the mechanism by which PLP kills cancer cells effectively has not been sufficiently clarified. To comprehensively understand the PLP-induced PDT processes, we conduct multifaceted experiments using both normal cells and cancer cells originating from the same sources, namely, RGM1, a rat gastric epithelial cell line, and RGK1, a rat gastric mucosa-derived cancer-like mutant. We reveal that PLP enables highly effective cancer treatment through PDT by employing a unique mechanism that utilizes the process of autophagy. The dynamics of PLP-accumulated phagosomes immediately after light irradiation are found to be completely different between normal cells and cancer cells, and it becomes clear that this difference results in the manifestation of the characteristic effect of PDT when using PLP. Since PLP is originally developed as a drug delivery agent, this study also suggests the potential for intracellular drug delivery processes through PLP-induced autophagy.

Adenosine 5'-monophosphate-activated protein kinase (AMPK) negatively regulates the immunity and resistance to Vibrio alginolyticus of white shrimp, Penaeus vannamei

Shrimp immunology is vital in establishing prophylactic and therapeutic strategies for controlling pathological problems that threaten shrimp production. Apart from dietary treatments, the adenosine 5'-monophosphate-activated protein kinase (AMPK), an important regulatory enzyme that restores cellular energy balance during metabolic and physiological stress, is known to have therapeutic potential to improve shrimp's defense mechanism. Despite this, studies targeting the AMPK pathway in shrimp exposed to stressful conditions are vastly limited. In this study, AMPK was knocked down to assess the immunological changes and white shrimp, Penaeus vannamei resistance to Vibrio alginolyticus infection. Shrimps were injected individually and simultaneously with dsRNA targeting specific genes such as AMPK, Rheb, and TOR, after which the hepatopancreas was analyzed for the different gene expressions. The gene expressions of AMPK, Rheb, and TOR were effectively suppressed after being treated with dsRNAs. The Western blot analysis further confirmed a reduction in the protein concentration of AMPK and Rheb in the hepatopancreas. The suppression of AMPK gene led to a robust increase in the shrimp's resistance to V. alginolyticus, whereas the activation of AMPK by metformin decreased the shrimp's disease resistance. Among the mTOR downstream targets, the HIF-1α expression in shrimp treated with dsAMPK significantly increased at 48 h but returned to normal levels when shrimp were treated with dsAMPK and either dsRheb or dsTOR. Immune responses such as respiratory burst, lysozyme activity, and phagocytic activity increased, while superoxide dismutase activity decreased following the knockdown of the AMPK gene compared to the control group. However, co-injection with dsAMPK and dsTOR or dsRheb restored immune responses to normal levels. Collectively, these results demonstrate that the inactivation of AMPK may ameliorate shrimp's innate immune response to recognize and defend against pathogens via the AMPK/mTOR1 pathway.

A nutrigenomics approach to study the effects of ω-3 fatty acids in laying hens under physiological stress

Supplement of ω-3 fatty acids can decrease the harmful effects of stress. However, the potential molecular mechanisms that are modulated by dietary ω-3 fatty acids in laying hens under stress remain unknown. Hence, RNA-sequencing (RNA-Seq) technology was used to gain new insights into different gene expression profiles and potential pathways involved in response to stress in the liver of 35-week-old Lohmann LSL-Lite laying hens supplemented with ω-3. Three groups including control (non-stress), stress, and stress_ω-3 fatty acids (three layers per each group) were applied. A total of 1,321 genes were detected as differentially expressed genes of which 701, 1,049, and 86 DEGs belonged to stress vs. control, stress_ω-3 vs. control, and stress vs. stress_ω-3 pairwise comparisons, respectively. Gene ontology and KEGG pathway analysis indicated that the DEGs were enriched in particular regulation of steroid and cholesterol biosynthetic process, fatty acid degradation, AMPK signaling pathway, fatty acid biosynthesis, and immune response. Our data represented a promising approach regarding the importance of ω-3 as anxiolytic and anti-stress. In this context, UNC13B and ADRA1B genes were downregulated in the stress_ω-3 group compared to the stress group, which are associated with decreased activity of glutamatergic stimulatory neurons and probably play important role in facilitating the response to stress. This study extends the current understanding of the liver transcriptome response to physiological stress, and provides new insights into the molecular responses to stress in laying hens fed a diet supplemented with ω-3 fatty acids.

Unlocking the Full Potential of SGLT2 Inhibitors: Expanding Applications beyond Glycemic Control

The number of diabetic patients has risen dramatically in recent decades, owing mostly to the rising incidence of type 2 diabetes mellitus (T2DM). Several oral antidiabetic medications are used for the treatment of T2DM including, α-glucosidases inhibitors, biguanides, sulfonylureas, meglitinides, GLP-1 receptor agonists, PPAR-γ agonists, DDP4 inhibitors, and SGLT2 inhibitors. In this review we focus on the possible effects of SGLT2 inhibitors on different body systems. Beyond the diabetic state, SGLT2 inhibitors have revealed a demonstrable ability to ameliorate cardiac remodeling, enhance myocardial function, and lower heart failure mortality. Additionally, SGLT2 inhibitors can modify adipocytes and their production of cytokines, such as adipokines and adiponectin, which enhances insulin sensitivity and delays diabetes onset. On the other hand, SGLT2 inhibitors have been linked to decreased total hip bone mineral deposition and increased hip bone resorption in T2DM patients. More data are needed to evaluate the role of SGLT2 inhibitors on cancer. Finally, the effects of SGLT2 inhibitors on neuroprotection appear to be both direct and indirect, according to scientific investigations utilizing various experimental models. SGLT2 inhibitors improve vascular tone, elasticity, and contractility by reducing oxidative stress, inflammation, insulin signaling pathways, and endothelial cell proliferation. They also improve brain function, synaptic plasticity, acetylcholinesterase activity, and reduce amyloid plaque formation, as well as regulation of the mTOR pathway in the brain, which reduces brain damage and cognitive decline.

Promising Role of the Scutellaria baicalensis Root Hydroxyflavone-Baicalein in the Prevention and Treatment of Human Diseases

Plant roots, due to a high content of natural antioxidants for many years, have been used in herbal medicine. It has been documented that the extract of Baikal skullcap (Scutellaria baicalensis) has hepatoprotective, calming, antiallergic, and anti-inflammatory properties. Flavonoid compounds found in the extract, including baicalein, have strong antiradical activity, which improves overall health and increases feelings of well-being. Plant-derived bioactive compounds with antioxidant activity have for a long time been used as an alternative source of medicines to treat oxidative stress-related diseases. In this review, we summarized the latest reports on one of the most important aglycones with respect to the pharmacological activity and high content in Baikal skullcap, which is 5,6,7-trihydroxyflavone (baicalein).

AMPK inhibits liver gluconeogenesis: fact or fiction?

Is there a role for AMPK in the control of hepatic gluconeogenesis and could targeting AMPK in liver be a viable strategy for treating type 2 diabetes? These are frequently asked questions this review tries to answer. After describing properties of AMPK and different small-molecule AMPK activators, we briefly review the various mechanisms for controlling hepatic glucose production, mainly via gluconeogenesis. The different experimental and genetic models that have been used to draw conclusions about the role of AMPK in the control of liver gluconeogenesis are critically discussed. The effects of several anti-diabetic drugs, particularly metformin, on hepatic gluconeogenesis are also considered. We conclude that the main effect of AMPK activation pertinent to the control of hepatic gluconeogenesis is to antagonize glucagon signalling in the short-term and, in the long-term, to improve insulin sensitivity by reducing hepatic lipid content.

High oxygen-modified packaging (HiOx-MAP) mediates HIF-1α regulation of tenderness changes during postmortem aging of yak meat

In the present study, we studied the effect of high oxygen-modified packaging (HiOx-MAP) on yak meat tenderness and the underlying mechanism. HiOx-MAP significantly increased the myofibril fragmentation index (MFI) of yak meat. In addition, western blotting showed that the expression of hypoxia-inducible factor (HIF-1α) and ryanodine receptors (RyR) in the HiOx-MAP group was reduced. HiOx-MAP increased the activity of sarcoplasmic reticulum calcium-ATPase (SERCA). The energy disperse spectroscopy (EDS) mapping showed gradually reduced calcium distribution in the treated endoplasmic reticulum. Furthermore, HiOx-MAP treatment increased the caspase-3 activity and the apoptosis rate. The activity of calmodulin protein (CaMKKβ) and AMP-activated protein kinase (AMPK) was down-regulated leading to apoptosis. These results indicated that HiOx-MAP promoted apoptosis during postmortem aging to improve the tenderization of meat.

Molecular Mechanisms for Ketone Body Metabolism, Signaling Functions, and Therapeutic Potential in Cancer

The ketone bodies (KBs) β-hydroxybutyrate and acetoacetate are important alternative energy sources for glucose during nutrient deprivation. KBs synthesized by hepatic ketogenesis are catabolized to acetyl-CoA through ketolysis in extrahepatic tissues, followed by the tricarboxylic acid cycle and electron transport chain for ATP production. Ketogenesis and ketolysis are regulated by the key rate-limiting enzymes, 3-hydroxy-3-methylglutaryl-CoA synthase 2 and succinyl-CoA:3-oxoacid-CoA transferase, respectively. KBs participate in various cellular processes as signaling molecules. KBs bind to G protein-coupled receptors. The most abundant KB, β-hydroxybutyrate, regulates gene expression and other cellular functions by inducing post-translational modifications. KBs protect tissues by regulating inflammation and oxidative stress. Recently, interest in KBs has been increasing due to their potential for treatment of various diseases such as neurological and cardiovascular diseases and cancer. Cancer cells reprogram their metabolism to maintain rapid cell growth and proliferation. Dysregulation of KB metabolism also plays a role in tumorigenesis in various types of cancer. Targeting metabolic changes through dietary interventions, including fasting and ketogenic diets, has shown beneficial effects in cancer therapy. Here, we review current knowledge of the molecular mechanisms involved in the regulation of KB metabolism and cellular signaling functions, and the therapeutic potential of KBs and ketogenic diets in cancer.

The pathophysiology of major depressive disorder through the lens of systems biology: Network analysis of the psycho-immune-neuroendocrine physiome

BACKGROUND/AIMS

The psycho-immune-neuroendocrine (PINE) network is a predominantly physiological (metabolomic) model constructed from the literature, inter-linking multiple biological processes associated with major depressive disorder (MDD), thereby integrating putative mechanistic pathways for MDD into a single network.

MATERIAL AND METHODS

Previously published metabolomic pathways for the PINE network based on literature searches conducted in 1991-2021 were used to construct an edge table summarizing all physiological pathways in pairs of origin nodes and target nodes. The Gephi software program was used to calculate network metrics from the edge table, including total degree and centrality measures, to ascertain key network nodes and construct a directed network graph.

RESULTS

An edge table and directional network graph of physiological relationships in the PINE network is presented. The network has properties consistent with complex biological systems, with analysis yielding key network nodes comprising pro-inflammatory cytokines (TNF- α, IL6 and IL1), glucocorticoids and corticotropin releasing hormone (CRH). These may represent central structural and regulatory elements in the context of MDD.

CONCLUSION

The identified hubs have a high degree of connection and are known to play roles in the progression from health to MDD. These nodes represent strategic targets for therapeutic intervention or prevention. Future work is required to build a weighted and dynamic simulation of the network PINE.

Effect of black soldier fly (Hermetia illucens) larvae meal on lipid and glucose metabolism of Pacific white shrimp Litopenaeus vannamei

The present study investigated the effect of black soldier fly (Hermetia illucens) larvae meal (BSF) on haemolymph biochemical indicators, muscle metabolites as well as the lipid and glucose metabolism of Pacific white shrimp Litopenaeus vannamei. Four diets were formulated in which the control diet contained 25 % of fishmeal (FM) and 10 % (BSF10), 20 % (BSF20), and 30 % (BSF30) of FM protein were replaced with BSF. Four hundred and eighty shrimp (0·88 ± 0·00 g) were distributed to four groups of three replicates and fed for 7 weeks. Results showed that growth performance of shrimp fed BSF30 significantly decreased compared with those fed FM, but there was no significant difference in survival among groups. The whole shrimp crude lipid content, haemolymph TAG and total cholesterol were decreased with the increasing BSF inclusion. The results of metabolomics showed that the metabolite patterns of shrimp fed different diets were altered, with significant changes in metabolites related to lipid metabolism, glucose metabolism as well as TCA cycle. The mRNA expressions of hk, pfk, pk, pepck, ampk, mcd, cpt-1 and scd1 in hepatopancreas were downregulated in shrimp fed BSF30, but mRNA expression of acc1 was upregulated. Unlike BSF30, the mRNA expressions of fas, cpt-1, fbp and 6pgd in hepatopancreas were upregulated in shrimp fed BSF20. This study indicates that BSF20 diet promoted lipid synthesis and lipolysis, while BSF30 diet weakened β-oxidation and glycolysis as well as affected the unsaturated fatty acids synthesis, which may affect the growth performance and body composition of shrimp.

Acetyl-CoA synthetase 2(ACSS2): a review with a focus on metabolism and tumor development

Acetyl-CoA synthetase 2 (ACSS2), an important member of the acetyl-CoA synthetase (ACSS) family, can catalyze the conversion of acetate to acetyl coenzyme A (acetyl-CoA). Currently, acetyl-CoA is considered an important intermediate metabolite in the metabolism of energy substrates. In addition, nutrients converge through acetyl-CoA into a common metabolic pathway, the tricarboxylic acid cycle and oxidative phosphorylation. Not only does ACSS2 play a crucial role in material energy metabolism, it is also involved in the regulation of various acetylation processes, such as regulation of histone and transcription factor acetylation. ACSS2-mediated regulation of acetylation is related to substance metabolism and tumorigenesis. In mammalian cells, ACSS2 utilizes intracellular acetate to synthesize acetyl-CoA, a step in the process of DNA and histone acetylation. In addition, studies in tumors have shown that cancer cells adapt to the growth conditions in the tumor microenvironment (TME) by activating or increasing the expression level of ACSS2 under metabolic stress. Therefore, this review mainly outlines the role of ACSS2 in substance metabolism and tumors and provides insights useful for investigating ACSS2 as a therapeutic target.

Inhibition of basal and glucagon-induced hepatic glucose production by 991 and other pharmacological AMPK activators

Pharmacological AMPK activation represents an attractive approach for the treatment of type 2 diabetes (T2D). AMPK activation increases skeletal muscle glucose uptake, but there is controversy as to whether AMPK activation also inhibits hepatic glucose production (HGP) and pharmacological AMPK activators can have off-target effects that contribute to their anti-diabetic properties. The main aim was to investigate the effects of 991 and other direct AMPK activators on HGP and determine whether the observed effects were AMPK-dependent. In incubated hepatocytes, 991 substantially decreased gluconeogenesis from lactate, pyruvate and glycerol, but not from other substrates. Hepatocytes from AMPKβ1-/- mice had substantially reduced liver AMPK activity, yet the inhibition of glucose production by 991 persisted. Also, the glucose-lowering effect of 991 was still seen in AMPKβ1-/- mice subjected to an intraperitoneal pyruvate tolerance test. The AMPK-independent mechanism by which 991 treatment decreased gluconeogenesis could be explained by inhibition of mitochondrial pyruvate uptake and inhibition of mitochondrial sn-glycerol-3-phosphate dehydrogenase-2. However, 991 and new-generation direct small-molecule AMPK activators antagonized glucagon-induced gluconeogenesis in an AMPK-dependent manner. Our studies support the notion that direct pharmacological activation of hepatic AMPK as well as inhibition of pyruvate uptake could be an option for the treatment of T2D-linked hyperglycemia.

Effects of Downhill Running Exercise on Glucose Tolerance and Skeletal Muscle P-AMPK Expression in Type II Diabetes Rats

OBJECTIVES The purpose of this study was to investigate the effects of moderate downhill running exercise on glucose tolerance and skeletal muscle phospho-AMP activated protein kinase(P-AMPK) expression in type Ⅱ diabetes rats.METHODS 8-week-old, 24 wistar & GK rats (type Ⅱ diabetes model) were randomly divided into 4 groups, NR, NE, DR, DE. Downhill running treatment were performed on the treadmill at the -16 % and speed of 16m/min for 1 hour. All groups were done with Oral glucose tolerance test(OGTT) and after 1 week washout period, rats in exercise groups performed downhill running. After exercise treatment, soleus muscle of rats were extracted for test of P-AMPK expression.RESULTS In OGTT, blood glucose levels in all groups were increased after the oral glucose load and these were significantly differ from rest level. But in DE group, blood glucose level at 120 min after OGTT was not significantly differ from rest level. In immunoblotting test for P-AMPK expression of skeletal muscle, NE group was significantly higher than NR group and DE group was significantly higher than other groups.CONCLUSIONS Downhill running exercise improved glucose tolerance and increased P-AMPK expression of skeletal muscle in type Ⅱ diabetes rats.

Regulation of appetite-related neuropeptides by Panax ginseng: A novel approach for obesity treatment

Obesity is a primary factor provoking various chronic disorders, including cardiovascular disease, diabetes, and cancer, and causes the death of 2.8 million individuals each year. Diet, physical activity, medications, and surgery are the main therapies for overweightness and obesity. During weight loss therapy, a decrease in energy stores activates appetite signaling pathways under the regulation of neuropeptides, including anorexigenic [corticotropin-releasing hormone, proopiomelanocortin (POMC), cholecystokinin (CCK), and cocaine- and amphetamine-regulated transcript] and orexigenic [agouti-related protein (AgRP), neuropeptide Y (NPY), and melanin-concentrating hormone] neuropeptides, which increase food intake and lead to failure in attaining weight loss goals. Ginseng and ginsenosides reverse these signaling pathways by suppressing orexigenic neuropeptides (NPY and AgRP) and provoking anorexigenic neuropeptides (CCK and POMC), which prevent the increase in food intake. Moreover, the results of network pharmacology analysis have revealed that constituents of ginseng radix, including campesterol, beta-elemene, ginsenoside Rb1, biotin, and pantothenic acid, are highly correlated with neuropeptide genes that regulate energy balance and food intake, including ADIPOQ, NAMPT, UBL5, NUCB2, LEP, CCK, GAST, IGF1, RLN1, PENK, PDYN, and POMC. Based on previous studies and network pharmacology analysis data, ginseng and its compounds may be a potent source for obesity treatment by regulating neuropeptides associated with appetite.

Association Between Gut Microbiota and Osteoarthritis: A Review of Evidence for Potential Mechanisms and Therapeutics

Osteoarthritis (OA) is a multifactorial joint disease characterized by degeneration of articular cartilage, which leads to joints pain, disability and reduced quality of life in patients with OA. Interpreting the potential mechanisms underlying OA pathogenesis is crucial to the development of new disease modifying treatments. Although multiple factors contribute to the initiation and progression of OA, gut microbiota has gradually been regarded as an important pathogenic factor in the development of OA. Gut microbiota can be regarded as a multifunctional “organ”, closely related to a series of immune, metabolic and neurological functions. This review summarized research evidences supporting the correlation between gut microbiota and OA, and interpreted the potential mechanisms underlying the correlation from four aspects: immune system, metabolism, gut-brain axis and gut microbiota modulation. Future research should focus on whether there are specific gut microbiota composition or even specific pathogens and the corresponding signaling pathways that contribute to the initiation and progression of OA, and validate the potential of targeting gut microbiota for the treatment of patients with OA.

Treadmill exercise ameliorates ethanol with lipopolysaccharide and carbon tetrachloride-mediated liver injury in mice

We reported that application of ethanol with lipopolysaccharide (LPS) and carbon tetrachloride (CCl₄) enhanced alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level. In the current experiment, the protective effect of treadmill running on liver injury caused by ethanol with LPS and CCl₄ in mice was studied. Liver injury severity was determined by measuring ALT and AST level in the blood. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, immunohistochemistry for caspase-3, and Western blotting for Bcl-2-associated X protein (Bax) and B-cell lymphoma 2 (Bcl-2) were performed to indicate hepatocyte apoptosis. In addition, to understand the mechanism, 5′-adenosine monophosphate-activated protein kinase (AMPK) phosphorylation was studied by Western blotting. Treadmill exercise ameliorated ethanol with LPS and CCl₄-mediated elevation of ALT and AST level. Treadmill exercise suppressed ethanol with LPS and CCl₄-mediated elevation of the TUNEL-positive cell number and cleaved caspase-3 expression. Treadmill exercise suppressed ethanol with LPS and CCl₄-mediated elevation of Bax expression and increased Bcl-2 expression suppressed by application of ethanol with LPS and CCl₄. Treadmill exercise enhanced AMPK phosphorylation which was suppressed by application of ethanol with LPS and CCl₄. Treadmill exercise has the effect of reducing liver damage caused by alcohol and or drug addiction.

Metformin and Insulin Resistance: A Review of the Underlying Mechanisms behind Changes in GLUT4-Mediated Glucose Transport

Metformin is the most commonly used treatment to increase insulin sensitivity in insulin-resistant (IR) conditions such as diabetes, prediabetes, polycystic ovary syndrome, and obesity. There is a well-documented correlation between glucose transporter 4 (GLUT4) expression and the level of IR. Therefore, the observed increase in peripheral glucose utilization after metformin treatment most likely comes from the induction of GLUT4 expression and its increased translocation to the plasma membrane. However, the mechanisms behind this effect and the critical metformin targets are still largely undefined. The present review explores the evidence for the crucial role of changes in the expression and activation of insulin signaling pathway mediators, AMPK, several GLUT4 translocation mediators, and the effect of posttranscriptional modifications based on previously published preclinical and clinical models of metformin’s mode of action in animal and human studies. Our aim is to provide a comprehensive review of the studies in this field in order to shed some light on the complex interactions between metformin action, GLUT4 expression, GLUT4 translocation, and the observed increase in peripheral insulin sensitivity.

An overview of pharmacological activities of baicalin and its aglycone baicalein: New insights into molecular mechanisms and signaling pathways

The flavonoids, baicalin, and its aglycone baicalein possess multi-fold therapeutic properties and are mainly found in the roots of Oroxylum indicum (L.) Kurz and Scutellaria baicalensis Georgi. These flavonoids have been reported to possess various pharmacological properties, including antibacterial, antiviral, anticancer, anticonvulsant, anti-oxidant, hepatoprotective, and neuroprotective effects. The pharmacological properties of baicalin and baicalein are due to their abilities to scavenge reactive oxygen species (ROS) and interaction with various signaling molecules associated with apoptosis, inflammation, autophagy, cell cycle, mitochondrial dynamics, and cytoprotection. In this review, we summarized the molecular mechanisms underlying the chemopreventive and chemotherapeutic applications of baicalin and baicalein in the treatment of cancer and inflammatory diseases. In addition, the preventive effects of baicalin and baicalein on mitochondrial dynamics and functions were highlighted with a particular emphasis on their anti-oxidative and cytoprotective properties. The current review highlights could be useful for future prospective studies to further improve the pharmacological applications of baicalein and baicalin. These studies should define the threshold for optimal drug exposure, dose optimization and focus on therapeutic drug monitoring, objective disease markers, and baicalin/baicalein drug levels.

Adiponectin: a pleiotropic hormone with multifaceted roles

Adipose tissue mostly composed of different types of fat is one of the largest endocrine organs in the body playing multiple intricate roles including but not limited to energy storage, metabolic homeostasis, generation of heat, participation in immune functions and secretion of a number of biologically active factors known as adipokines. The most abundant of them is adiponectin. This adipocite-derived hormone exerts pleiotropic actions and exhibits insulin-sensitizing, antidiabetic, anti-obesogenic, anti-inflammatory, antiatherogenic, cardio- and neuroprotective properties. Contrariwise to its protective effects against various pathological events in different cell types, adiponectin may have links to several systemic diseases and malignances. Reduction in adiponectin levels has an implication in COVID-19-associated respiratory failure, which is attributed mainly to a phenomenon called 'adiponectin paradox'. Ample evidence about multiple functions of adiponectin in the body was obtained from animal, mostly rodent studies. Our succinct review is entirely about multifaceted roles of adiponectin and mechanisms of its action in different physiological and pathological states.

Imatinib protects against human beta-cell death via inhibition of mitochondrial respiration and activation of AMPK

The protein tyrosine kinase inhibitor imatinib is used in the treatment of various malignancies but may also promote beneficial effects in the treatment of diabetes. The aim of the present investigation was to characterize the mechanisms by which imatinib protects insulin producing cells. Treatment of non-obese diabetic (NOD) mice with imatinib resulted in increased beta-cell AMP-activated kinase (AMPK) phosphorylation. Imatinib activated AMPK also in vitro, resulting in decreased ribosomal protein S6 phosphorylation and protection against islet amyloid polypeptide (IAPP)-aggregation, thioredoxin interacting protein (TXNIP) up-regulation and beta-cell death. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) mimicked and compound C counteracted the effect of imatinib on beta-cell survival. Imatinib-induced AMPK activation was preceded by reduced glucose/pyruvate-dependent respiration, increased glycolysis rates, and a lowered ATP/AMP ratio. Imatinib augmented the fractional oxidation of fatty acids/malate, possibly via a direct interaction with the beta-oxidation enzyme enoyl coenzyme A hydratase, short chain, 1, mitochondrial (ECHS1). In non-beta cells, imatinib reduced respiratory chain complex I and II-mediated respiration and acyl-CoA carboxylase (ACC) phosphorylation, suggesting that mitochondrial effects of imatinib are not beta-cell specific. In conclusion, tyrosine kinase inhibitors modestly inhibit mitochondrial respiration, leading to AMPK activation and TXNIP down-regulation, which in turn protects against beta-cell death.

Alcohol Abstinence Rescues Hepatic Steatosis and Liver Injury via Improving Metabolic Reprogramming in Chronic Alcohol-Fed Mice

Background: Alcoholic liver disease (ALD) caused by chronic ethanol overconsumption is a common type of liver disease with a severe mortality burden throughout the world. The pathogenesis of ALD is complex, and no effective clinical treatment for the disease has advanced so far. Prolonged alcohol abstinence is the most effective therapy to attenuate the clinical course of ALD and even reverse liver damage. However, the molecular mechanisms involved in alcohol abstinence-improved recovery from alcoholic fatty liver remain unclear. This study aims to systematically evaluate the beneficial effect of alcohol abstinence on pathological changes in ALD.

Methods: Using the Lieber-DeCarli mouse model of ALD, we analysed whether 1-week alcohol withdrawal reversed alcohol-induced detrimental alterations, including oxidative stress, liver injury, lipids metabolism, and hepatic inflammation, by detecting biomarkers and potential targets.

Results: Alcohol withdrawal ameliorated alcohol-induced hepatic steatosis by improving liver lipid metabolism reprogramming via upregulating phosphorylated 5′-AMP -activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor-α (PPAR-α), and carnitine palmitoyltransferase-1 (CPT-1), and downregulating fatty acid synthase (FAS) and diacylglycerol acyltransferase-2 (DGAT-2). The activities of antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px), were significantly enhanced by alcohol withdrawal. Importantly, the abstinence recovered alcohol-fed induced liver injury, as evidenced by the improvements in haematoxylin and eosin (H&E) staining, plasma alanine aminotransferase (ALT) levels, and liver weight/body weight ratio. Alcohol-stimulated toll-like receptor 4/mitogen-activated protein kinases (TLR4/MAPKs) were significantly reversed by alcohol withdrawal, which might mechanistically contribute to the amelioration of liver injury. Accordingly, the hepatic inflammatory factor represented by tumour necrosis factor-alpha (TNF-α) was improved by alcohol abstinence.

Conclusion: In summary, we reported that alcohol withdrawal effectively restored hepatic lipid metabolism and reversed liver injury and inflammation by improving metabolism reprogramming. These findings enhanced our understanding of the biological mechanisms involved in the beneficial role of alcohol abstinence as an effective treatment for ALD.

AMPK in the gut-liver-brain axis and its influence on OP rats in an HSHF intake and WTD rat model

Obesogenic diets (ODs) can affect AMPK activation in several sites as the colon, liver, and hypothalamus. OD intake can impair the hypothalamic AMPK regulation of energy homeostasis. Despite consuming ODs, not all subjects have the propensity to develop or progress to obesity. The obesity propensity is more associated with energy intake than expenditure dysregulations and may have a link with AMPK activity. While the effects of ODs are studied widely, few evaluate the short-term effects of terminating OD intake. Withdrawing from OD (WTD) is thought to improve or reverse the damages caused by the intake. Therefore, here we applied an OD intake and WTD protocol aiming to evaluate AMPK protein content and phosphorylation in the colon, liver, and hypothalamus and their relationship with obesity propensity. To this end, male Wistar rats (60 days) received control or high-sugar/high-fat (HSHF) OD for 30 days. Half of the animals were OD-withdrawn and fed the control diet for 48 h. After intake, we found a reduction in AMPK phosphorylation in the hypothalamus and colon, and after WTD, we found an increase in its hepatic and hypothalamic phosphorylation. The decrease in colon pAMPK/AMPK could be linked with hypothalamic pAMPK/AMPK after HSHF intake, while the increase in hepatic pAMPK/AMPK could have prevented the increase in hypothalamic pAMPK/AMPK. In the obesity-prone rats, we found higher levels of hypothalamic and colon pAMPK/AMPK despite the higher body mass gain. Our results highlight the relevance in multi-organ investigations and animal phenotype evaluation when studying the energy metabolism regulations.

Autosomic dominant polycystic kidney disease and metformin: Old knowledge and new insights on retarding progression of chronic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common congenital kidney disorder, generally caused by mutations in the PKD1 and PKD2 genes, coding for polycystins 1 and 2. Its pathogenesis is accompanied by alterations of the cAMP, mTOR, MAPK/ERK, and JAK/STAT pathways. ADPKD is clinically characterized by the formation of many growing cysts with kidney enlargement and a progressive damage to the parenchyma, up to its complete loss of function, and the onset of end-stage renal disease (ESRD). The current aim of ADPKD therapy is the inhibition of cyst development and retardation of chronic kidney disease progression. Several drugs have been recently included as potential therapies for ADPKD including metformin, the drug of choice for the treatment of type 2 diabetes mellitus, according to its potential inhibitory effects on cystogenesis. In this review, we summarize preclinical and clinical evidence endorsing or rejecting metformin administration in ADPKD evolution and pathological mechanisms. We explored the biology of APDKD and the role of metformin in slowing down cystogenesis searching PubMed and Clinical Trials to identify relevant data from the database inception to December 2020. From our research analysis, evidence for metformin as emerging cure for ADPKD mainly arise from preclinical studies. In fact, clinical studies are still scanty and stronger evidence is awaited. Its effects are likely mediated by inhibition of the ERK pathway and increase of AMPK levels, which are both linked to ADPKD pathogenesis.

Human Placental Transcriptome Reveals Critical Alterations in Inflammation and Energy Metabolism with Fetal Sex Differences in Spontaneous Preterm Birth

A well-functioning placenta is crucial for normal gestation and regulates the nutrient, gas, and waste exchanges between the maternal and fetal circulations and is an important endocrine organ producing hormones that regulate both the maternal and fetal physiologies during pregnancy. Placental insufficiency is implicated in spontaneous preterm birth (SPTB). We proposed that deficits in the capacity of the placenta to maintain bioenergetic and metabolic stability during pregnancy may ultimately result in SPTB. To explore our hypothesis, we performed a RNA-seq study in male and female placentas from women with SPTB (<36 weeks gestation) compared to normal pregnancies (≥38 weeks gestation) to assess the alterations in the gene expression profiles. We focused exclusively on Black women (cases and controls), who are at the highest risk of SPTB. Six hundred and seventy differentially expressed genes were identified in male SPTB placentas. Among them, 313 and 357 transcripts were increased and decreased, respectively. In contrast, only 61 differentially expressed genes were identified in female SPTB placenta. The ingenuity pathway analysis showed alterations in the genes and canonical pathways critical for regulating inflammation, oxidative stress, detoxification, mitochondrial function, energy metabolism, and the extracellular matrix. Many upstream regulators and master regulators important for nutrient-sensing and metabolism were also altered in SPTB placentas, including the PI3K complex, TGFB1/SMADs, SMARCA4, TP63, CDKN2A, BRCA1, and NFAT. The transcriptome was integrated with published human placental metabolome to assess the interactions of altered genes and metabolites. Collectively, significant and biologically relevant alterations in the transcriptome were identified in SPTB placentas with fetal sex disparities. Altered energy metabolism, mitochondrial function, inflammation, and detoxification may underly the mechanisms of placental dysfunction in SPTB.

AMPK is indispensable for overload-induced muscle glucose uptake and glycogenesis but dispensable for inducing hypertrophy in mice

Chronic muscle loading (overload) induces skeletal muscles to undergo hypertrophy and to increase glucose uptake. Although AMP-activated protein kinase (AMPK) reportedly serves as a negative regulator of hypertrophy and a positive regulator of glucose uptake, its role in overload-induced skeletal muscle hypertrophy and glucose uptake is unclear. This study aimed to determine whether AMPK regulates overload-induced hypertrophy and glucose uptake in skeletal muscles. To this end, skeletal muscle overload was induced through unilateral synergist ablations in wild-type (WT) and transgenic mice, expressing the dominant-negative mutation of AMPK (AMPK-DN). After 14 days, parameters, including muscle fiber cross-sectional area (CSA), glycogen level, and in vivo [³ H]-2-deoxy-D-glucose uptake, were assessed. No significant difference was observed in body weight or blood glucose level between the WT and AMPK-DN mice. However, the 14-day muscle overload activated the AMPK pathway in WT mice skeletal muscle, whereas this response was impaired in the AMPK-DN mice. Despite a normal CSA gain in each fiber type, the AMPK-DN mice demonstrated a significant impairment of overload-induced muscle glucose uptake and glycogenesis, compared to WT mice. Moreover, 14-day overload-induced changes in GLUT4 and HKII expression levels were reduced in AMPK-DN mice, compared to WT mice. This study demonstrated that AMPK activation is indispensable for overload-induced muscle glucose uptake and glycogenesis; however, it is dispensable for the induction of hypertrophy in AMPK-DN mice. Furthermore, the AMPK/GLUT4 and HKII axes may regulate overload-induced muscle glucose uptake and glycogenesis.

Effects of Bacillus Subtilis-Fermented White Sword Bean Extract on Adipogenesis and Lipolysis of 3T3-L1 Adipocytes

To investigate the adipogenesis and lipolysis effects of the Bacillus subtilis-fermented white sword bean extract (FWSBE) on 3T3-L1 adipocytes, we treated 3T3-L1 preadipocytes before and after differentiation with FWSBE and measured triglyceride, free glycerol, mRNA, and protein levels. First, FWSBE reduced the cell viability of 3T3-L1 pre-adipocytes under 1000 µg/mL conditions. Triglyceride accumulation in 3T3-L1 pre-adipocytes was suppressed, and free glycerol content in mature 3T3-L1 adipocytes was increased in the FWSBE treatment groups, indicating that FWSBE has anti-obesity effects. Further, FWSBE suppressed adipogenesis in 3T3-L1 pre-adipocytes by lowering the protein levels of C/EBPα, PPARγ, and FAS and increasing the level of pACC and pAMPK. Additionally, FWSBE promoted lipolysis in mature 3T3-L1 adipocytes by increasing the transcription levels of Ppara, Acox, and Lcad and the protein levels of pHSL and ATGL. Thus, we suggest that FWSBE can be a potential dietary supplement because of its anti-obesity properties.

Proteomic Analysis Reveals That Metformin Suppresses PSMD2, STIP1, and CAP1 for Preventing Gastric Cancer AGS Cell Proliferation and Migration

Metformin is one of the most widely used anti-diabetic drugs in type-II diabetes treatment. The mechanism of decreasing blood glucose is believed to suppress hepatic gluconeogenesis by increasing muscular glucose uptake and insulin sensitivity. Recent studies suggest that metformin may reduce cancer risk; however, its anticancer mechanism in gastric cancers remains unclear. Here, we aim to evaluate the anticancer effects of metformin on human gastric adenocarcinoma (AGS) cells. Our results showed that metformin inhibited AGS cell proliferation in a dose-dependent manner. Using small-scale quantitative proteomics, we identified 177 differentially expressed proteins upon metformin treatment; among these, nine proteins such as 26S proteasome non-ATPase regulatory subunit 2 (PSMD2), stress-induced phosphoprotein 1 (STIP1), and adenylyl cyclase-associated protein 1 (CAP1) were significantly altered. We found that metformin induced cell cycle arrest at the G0/G1 phase, suppressed cell migration, and affected cytoskeleton distribution. Additionally, patients with highly expressed PSMD2, STIP1, and CAP1 have a poor clinical outcome. Our study provides a novel view of developing therapies for gastric cancer.

Effect of ACG-1, an Extract Blend of Angelica gigas, Cynanchum wilfordii, and Ginkgo biloba, on Blood Circulation Improvement Via Antiplatelet Aggregation and Antihyperlipidemia

Thrombosis causes poor blood circulation, which may lead to several cardiovascular disorders. Antiplatelet aggregation and antihyperlipidemia are the key processes that improve blood circulation. The antiplatelet aggregation and antihyperlipidemic effects of ACG-1, a mixture of Angelica gigas, Cynanchum wilfordii, and Ginkgo biloba extracts, were investigated in this study. The antiplatelet aggregation activity of ACG-1 was determined by studying its effects on collagen-induced platelet aggregation in human platelet-rich plasma (PRP). In addition, the effects of ACG-1 were investigated in a thromboembolism mouse model. The high-fat diet (HFD)-fed mouse model was used to investigate the antihyperlipidemic effects of ACG-1 and western blotting assay was performed to elucidate its mechanism of action. It was observed that ACG-1 significantly inhibited platelet aggregation in human PRP. Furthermore, ACG-1 showed protective effects in a thromboembolism mouse model induced by administering a mixed collagen and epinephrine intravenous injection. Oral administration of ACG-1 also significantly ameliorated blood lipid profiles in the HFD-fed mouse model. In conclusion, ACG-1 should be considered a powerful functional food to improve blood circulation.

Sirtuins-Mediated System-Level Regulation of Mammalian Tissues at the Interface between Metabolism and Cell Cycle: A Systematic Review

Sirtuins are a family of highly conserved NAD+-dependent proteins and this dependency links Sirtuins directly to metabolism. Sirtuins' activity has been shown to extend the lifespan of several organisms and mainly through the post-translational modification of their many target proteins, with deacetylation being the most common modification. The seven mammalian Sirtuins, SIRT1 through SIRT7, have been implicated in regulating physiological responses to metabolism and stress by acting as nutrient sensors, linking environmental and nutrient signals to mammalian metabolic homeostasis. Furthermore, mammalian Sirtuins have been implicated in playing major roles in mammalian pathophysiological conditions such as inflammation, obesity and cancer. Mammalian Sirtuins are expressed heterogeneously among different organs and tissues, and the same holds true for their substrates. Thus, the function of mammalian Sirtuins together with their substrates is expected to vary among tissues. Any therapy depending on Sirtuins could therefore have different local as well as systemic effects. Here, an introduction to processes relevant for the actions of Sirtuins, such as metabolism and cell cycle, will be followed by reasoning on the system-level function of Sirtuins and their substrates in different mammalian tissues. Their involvement in the healthy metabolism and metabolic disorders will be reviewed and critically discussed.

Metformin Improves Biochemical and Pathophysiological Changes in Hepatocellular Carcinoma with Pre-Existed Diabetes Mellitus Rats

Hepatocellular carcinoma (HCC) is one of the world’s most widely recognized malignant tumors that accounts for 90% of all the primary liver cancers and is a major cause of death from cancer, representing half a million deaths per year. Obesity and associated metabolic irregularities, particularly diabetes mellitus (DM) and insulin resistance, are important risk factors for the advancement of HCC. Recently, retrospective studies showed that metformin (MET) could protect the hepatic tissues in pre-existing diabetes mellitus from HCC. The purpose of this study was to assess the role of MET treatment in the pre-existing diabetic rats before and after HCC induction by diethylnitrosamine (DEN). Thirty-five male Sprague Dawley albino rats were partitioned into the following groups: Group 1 (Gp1) was the control. Gp2 was injected intraperitoneally (i.p) with streptozotocin (STZ) (80 mg/kg) and DEN (50 mg/kg/7 weeks). Gp3, Gp4, and Gp5 were injected as in Gp2 and treated with MET (150 mg/kg) before and/or after HCC induction. Biochemical parameters including liver functions, lipid profile, and oxidative stress biomarkers were determined. Furthermore, histological and immunohistochemical changes were assessed in all groups. Our results illustrated that the group of rats that were treated with STZ and DEN had significant changes in both liver functions and were associated with alterations in the liver histopathological architectures. Treatment with MET before or after HCC induction ameliorated the cellular changes in the liver tissues; however, the utmost protection was found in a group of rats, which were treated with MET before and after HCC induction.

Cudratricusxanthone A Inhibits Lipid Accumulation and Expression of Inducible Nitric Oxide Synthase in 3T3-L1 Preadipocytes

Cudratricusxanthone A (CTXA) is a natural bioactive compound extracted from the roots of Cudrania tricuspidata Bureau and has been shown to possess anti-inflammatory, anti-proliferative, and hepatoprotective activities. However, at present, anti-adipogenic and anti-inflammatory effects of CTXA on adipocytes remain unclear. In this study, we investigated the effects of CTXA on lipid accumulation and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, two known inflammatory enzymes, in 3T3-L1 preadipocytes. Strikingly, CTXA at 10 µM markedly inhibited lipid accumulation and reduced triglyceride (TG) content during 3T3-L1 preadipocyte differentiation with no cytotoxicity. On mechanistic levels, CTXA at 10 µM suppressed not only expression levels of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), and perilipin A, but also phosphorylation levels of signal transducer and activator of transcription-3 (STAT-3) and STAT-5 during 3T3-L1 preadipocyte differentiation. In addition, CTXA at 10 µM up-regulated phosphorylation levels of cAMP-activated protein kinase (AMPK) while down-regulating expression and phosphorylation levels of acetyl-CoA carboxylase (ACC) during 3T3-L1 preadipocyte differentiation. Moreover, CTXA at 10 µM greatly attenuated tumor necrosis factor (TNF)-α-induced expression of iNOS, but not COX-2, in 3T3-L1 preadipocytes. These results collectively demonstrate that CTXA has strong anti-adipogenic and anti-inflammatory effects on 3T3-L1 cells through control of the expression and phosphorylation levels of C/EBP-α, PPAR-γ, FAS, ACC, perilipin A, STAT-3/5, AMPK, and iNOS.

Identification of Differentially Expressed Genes and Lipid Metabolism Signaling Pathways between Muscle and Fat Tissues in Broiler Chickens

In this study, signaling pathways and key differentially expressed genes (DEGs) involved in lipid metabolism in muscle and fat tissues were investigated. Muscle and abdominal fat tissues were obtained from 35-day-old female broilers for RNA sequencing. DEGs between muscle and fat tissues were identified. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of DEGs were performed. A total of 6130 DEGs were identified to be significantly enriched in 365 GO terms, most of which were involved in biological processes, cellular components, and molecular functions in muscle and fat tissues. Three important lipid signaling pathways (pyruvate metabolism, the insulin signaling pathway, and the adipocytokine signaling pathway) were identified among the fat and muscle tissues of broilers. The key common DEGs in these pathways included phosphoenolpyruvate carboxykinase 2 (PCK2), acetyl-CoA carboxylase 1 alpha and beta (ACACA and ACACB), and the mitogen-activated protein kinase (AMPK) gene family. Hence, our findings revealed the pathways and key genes and gene families involved in the regulation of fat deposition in the muscle and fat tissues of broilers.

AMP-Activated Protein Kinase: Do We Need Activators or Inhibitors to Treat or Prevent Cancer?

AMP-activated protein kinase (AMPK) is a key regulator of cellular energy balance. In response to metabolic stress, it acts to redress energy imbalance through promotion of ATP-generating catabolic processes and inhibition of ATP-consuming processes, including cell growth and proliferation. While findings that AMPK was a downstream effector of the tumour suppressor LKB1 indicated that it might act to repress tumourigenesis, more recent evidence suggests that AMPK can either suppress or promote cancer, depending on the context. Prior to tumourigenesis AMPK may indeed restrain aberrant growth, but once a cancer has arisen, AMPK may instead support survival of the cancer cells by adjusting their rate of growth to match their energy supply, as well as promoting genome stability. The two isoforms of the AMPK catalytic subunit may have distinct functions in human cancers, with the AMPK-α1 gene often being amplified, while the AMPK-α2 gene is more often mutated. The prevalence of metabolic disorders, such as obesity and Type 2 diabetes, has led to the development of a wide range of AMPK-activating drugs. While these might be useful as preventative therapeutics in individuals predisposed to cancer, it seems more likely that AMPK inhibitors, whose development has lagged behind that of activators, would be efficacious for the treatment of pre-existing cancers.

Role of AMP-activated protein kinase on cardio-metabolic abnormalities in the development of diabetic cardiomyopathy: A molecular landscape

Cardiovascular complications associated with diabetes mellitus remains a leading cause of morbidity and mortality across the world. Diabetic cardiomyopathy is a descriptive pathology that in absence of co-morbidities such as hypertension, dyslipidemia initially characterized by cardiac stiffness, myocardial fibrosis, ventricular hypertrophy, and remodeling. These abnormalities further contribute to diastolic dysfunctions followed by systolic dysfunctions and eventually results in clinical heart failure (HF). The clinical outcomes associated with HF are considerably worse in patients with diabetes. The complexity of the pathogenesis and clinical features of diabetic cardiomyopathy raises serious questions in developing a therapeutic strategy to manage cardio-metabolic abnormalities. Despite extensive research in the past decade the compelling approaches to manage and treat diabetic cardiomyopathy are limited. AMP-Activated Protein Kinase (AMPK), a serine-threonine kinase, often referred to as cellular "metabolic master switch". During the development and progression of diabetic cardiomyopathy, a plethora of evidence demonstrate the beneficial role of AMPK on cardio-metabolic abnormalities including altered substrate utilization, impaired cardiac insulin metabolic signaling, mitochondrial dysfunction and oxidative stress, myocardial inflammation, increased accumulation of advanced glycation end-products, impaired cardiac calcium handling, maladaptive activation of the renin-angiotensin-aldosterone system, endoplasmic reticulum stress, myocardial fibrosis, ventricular hypertrophy, cardiac apoptosis, and impaired autophagy. Therefore, in this review, we have summarized the findings from pre-clinical and clinical studies and provided a collective overview of the pathophysiological mechanism and the regulatory role of AMPK on cardio-metabolic abnormalities during the development of diabetic cardiomyopathy.

Transcriptomic and Quantitative Proteomic Profiling Reveals Signaling Pathways Critical for Pancreatic Islet Maturation

Pancreatic β-cell dysfunction and reduced insulin secretion play a key role in the pathogenesis of diabetes. Fetal and neonatal islets are functionally immature and have blunted glucose responsiveness and decreased insulin secretion in response to stimuli and are far more proliferative. However, the mechanisms underlying functional immaturity are not well understood. Pancreatic islets are composed of a mixture of different cell types, and the microenvironment of islets and interactions between these cell types are critical for β-cell development and maturation. RNA sequencing and quantitative proteomic data from intact islets isolated from fetal (embryonic day 19) and 2-week-old Sprague-Dawley rats were integrated to compare their gene and protein expression profiles. Ingenuity Pathway Analysis (IPA) was also applied to elucidate pathways and upstream regulators modulating functional maturation of islets. By integrating transcriptome and proteomic data, 917 differentially expressed genes/proteins were identified with a false discovery rate of less than 0.05. A total of 411 and 506 of them were upregulated and downregulated in the 2-week-old islets, respectively. IPA revealed novel critical pathways associated with functional maturation of islets, such as AMPK (adenosine monophosphate-activated protein kinase) and aryl hydrocarbon receptor signaling, as well as the importance of lipid homeostasis/signaling and neuronal function. Furthermore, we also identified many proteins enriched either in fetal or 2-week-old islets related to extracellular matrix and cell communication, suggesting that these pathways play critical roles in islet maturation. Our present study identified novel pathways for mature islet function in addition to confirming previously reported mechanisms, and provided new mechanistic insights for future research on diabetes prevention and treatment.

Comparative Study of the Effects of Light Controlled Germination Conditions on Saponarin Content in Barley Sprouts and Lipid Accumulation Suppression in HepG2 Hepatocyte and 3T3-L1 Adipocyte Cells Using Barley Sprout Extracts

Barley sprouts (BS) contain physiologically active substances and promote various positive physiological functions in the human body. The levels of the physiologically active substances in plants depend on their growth conditions. In this study, BS were germinated using differently colored LED lights and different nutrient supplements. Overall, there were 238 varied BS samples analyzed for their total polyphenol and flavonoid contents. Principal component analysis (PCA) was performed to determine the relationship between the germinated samples and their total polyphenol and flavonoid contents, and those with high levels were further analyzed for their saponarin content. Based on the PCA plot, the optimal conditions for metabolite production were blue light with 0.1% boric acid supplementation. In vitro experiments using the ethanol extract from the BS cultured in blue light showed that the extract significantly inhibited the total lipid accumulation in 3T3-L1 adipocytes and the lipid droplets in HepG2 hepatocytes. These findings suggest that specific and controlled light source and nutrient conditions for BS growth could increase the production of secondary metabolites associated with inhibited fat accumulation in adipocytes and hepatocytes.

Metformin: A Prospective Alternative for the Treatment of Chronic Pain

Metformin (biguanide) is a drug widely used for the treatment of type 2 diabetes. This drug has been used for 60 years as a highly effective antihyperglycemic agent. The search for the mechanism of action of metformin has produced an enormous amount of research to explain its effects on gluconeogenesis, protein metabolism, fatty acid oxidation, oxidative stress, glucose uptake, autophagy and pain, among others. It was only up the end of the 1990s and beginning of this century that some of its mechanisms were revealed. Metformin induces its beneficial effects in diabetes through the activation of a master switch kinase named AMP-activated protein kinase (AMPK). Two upstream kinases account for the physiological activation of AMPK: liver kinase B1 and calcium/calmodulin-dependent protein kinase kinase 2. Once activated, AMPK inhibits the mechanistic target of rapamycin complex 1 (mTORC1), which in turn avoids the phosphorylation of p70 ribosomal protein S6 kinase 1 and phosphatidylinositol 3-kinase/protein kinase B signaling pathways and reduces cap-dependent translation initiation. Since metformin is a disease-modifying drug in type 2 diabetes, which reduces the mTORC1 signaling to induce its effects on neuronal plasticity, it was proposed that these mechanisms could also explain the antinociceptive effect of this drug in several models of chronic pain. These studies have highlighted the efficacy of this drug in chronic pain, such as that from neuropathy, insulin resistance, diabetic neuropathy, and fibromyalgia-type pain. Mounting evidence indicates that chronic pain may induce anxiety, depression and cognitive impairment in rodents and humans. Interestingly, metformin is able to reverse some of these consequences of pathological pain in rodents. The purpose of this review was to analyze the current evidence about the effects of metformin in chronic pain and three of its comorbidities (anxiety, depression and cognitive impairment).

Acetate Revisited: A Key Biomolecule at the Nexus of Metabolism, Epigenetics and Oncogenesis-Part 1: Acetyl-CoA, Acetogenesis and Acyl-CoA Short-Chain Synthetases

Acetate is a major end product of bacterial fermentation of fiber in the gut. Acetate, whether derived from the diet or from fermentation in the colon, has been implicated in a range of health benefits. Acetate is also generated in and released from various tissues including the intestine and liver, and is generated within all cells by deacetylation reactions. To be utilized, all acetate, regardless of the source, must be converted to acetyl coenzyme A (acetyl-CoA), which is carried out by enzymes known as acyl-CoA short-chain synthetases. Acyl-CoA short-chain synthetase-2 (ACSS2) is present in the cytosol and nuclei of many cell types, whereas ACSS1 is mitochondrial, with greatest expression in heart, skeletal muscle, and brown adipose tissue. In addition to acting to redistribute carbon systemically like a ketone body, acetate is becoming recognized as a cellular regulatory molecule with diverse functions beyond the formation of acetyl-CoA for energy derivation and lipogenesis. Acetate acts, in part, as a metabolic sensor linking nutrient balance and cellular stress responses with gene transcription and the regulation of protein function. ACSS2 is an important task-switching component of this sensory system wherein nutrient deprivation, hypoxia and other stressors shift ACSS2 from a lipogenic role in the cytoplasm to a regulatory role in the cell nucleus. Protein acetylation is a critical post-translational modification involved in regulating cell behavior, and alterations in protein acetylation status have been linked to multiple disease states, including cancer. Improving our fundamental understanding of the "acetylome" and how acetate is generated and utilized at the subcellular level in different cell types will provide much needed insight into normal and neoplastic cellular metabolism and the epigenetic regulation of phenotypic expression under different physiological stressors. This article is Part 1 of 2 - for Part 2 see doi: 10.3389/fphys.2020.580171.

Peroxisome Proliferator-Activated Receptors as Molecular Links between Caloric Restriction and Circadian Rhythm

The circadian rhythm plays a chief role in the adaptation of all bodily processes to internal and environmental changes on the daily basis. Next to light/dark phases, feeding patterns constitute the most essential element entraining daily oscillations, and therefore, timely and appropriate restrictive diets have a great capacity to restore the circadian rhythm. One of the restrictive nutritional approaches, caloric restriction (CR) achieves stunning results in extending health span and life span via coordinated changes in multiple biological functions from the molecular, cellular, to the whole-body levels. The main molecular pathways affected by CR include mTOR, insulin signaling, AMPK, and sirtuins. Members of the family of nuclear receptors, the three peroxisome proliferator-activated receptors (PPARs), PPARα, PPARβ/δ, and PPARγ take part in the modulation of these pathways. In this non-systematic review, we describe the molecular interconnection between circadian rhythm, CR-associated pathways, and PPARs. Further, we identify a link between circadian rhythm and the outcomes of CR on the whole-body level including oxidative stress, inflammation, and aging. Since PPARs contribute to many changes triggered by CR, we discuss the potential involvement of PPARs in bridging CR and circadian rhythm.

Intrauterine Inflammation Alters the Transcriptome and Metabolome in Placenta

Placental insufficiency is implicated in spontaneous preterm birth (SPTB) associated with intrauterine inflammation. We hypothesized that intrauterine inflammation leads to deficits in the capacity of the placenta to maintain bioenergetic and metabolic stability during pregnancy ultimately resulting in SPTB. Using a mouse model of intrauterine inflammation that leads to preterm delivery, we performed RNA-seq and metabolomics studies to assess how intrauterine inflammation alters gene expression and/or modulates metabolite production and abundance in the placenta. 1871 differentially expressed genes were identified in LPS-exposed placenta. Among them, 1,149 and 722 transcripts were increased and decreased, respectively. Ingenuity pathway analysis showed alterations in genes and canonical pathways critical for regulating oxidative stress, mitochondrial function, metabolisms of glucose and lipids, and vascular reactivity in LPS-exposed placenta. Many upstream regulators and master regulators important for nutrient-sensing and mitochondrial function were also altered in inflammation exposed placentae, including STAT1, HIF1α, mTOR, AMPK, and PPARα. Comprehensive quantification of metabolites demonstrated significant alterations in the glucose utilization, metabolisms of branched-chain amino acids, lipids, purine and pyrimidine, as well as carbon flow in TCA cycle in LPS-exposed placenta compared to control placenta. The transcriptome and metabolome were also integrated to assess the interactions of altered genes and metabolites. Collectively, significant and biologically relevant alterations in the placenta transcriptome and metabolome were identified in placentae exposed to intrauterine inflammation. Altered mitochondrial function and energy metabolism may underline the mechanisms of inflammation-induced placental dysfunction.

Activation of AMP-activated protein kinase signaling pathway ameliorates steatosis in laying hen hepatocytes

The fatty liver hemorrhage syndrome in laying hens is a disease of lipid metabolism disorders. Importantly, energy sensor AMP-activated protein kinase (AMPK) plays an essential role in homeostasis regulation of liver lipid. The current research aims to investigate the relationship between AMPK signaling pathway and lipid metabolism in laying hen hepatocytes and explore the underlying mechanisms. The steatotic hepatocytes model of laying hen was established and treated with AMPK agonist AICAR and inhibitor compound C. The results showed that the levels of triglyceride, total cholesterol, and low-density lipoprotein cholesterol significantly declined while high-density lipoprotein cholesterol level increased in the AICAR-treated steatosis group compared with the steatosis group. Furthermore, the mRNA levels of liver kinase B1 and AMP-activated protein kinase α1 declined significantly in the steatosis group compared with those in the normal group. However, AMPK activation significantly upregulated the mRNA levels of peroxisome proliferator-activated receptor α and carnitine palmitoyl transferase-1 while downregulated the mRNA levels of acetyl CoA carboxylase, fatty acid synthase, 3-hydroxy-3-methyl glutaryl coenzyme A reductase, Sn-glycerol-3-phosphate acyltransferase, and hepatocyte nuclear factor 4α. These results suggest that activated AMPK signaling pathway increases fatty acid oxidation and reduces lipid synthesis in laying hen hepatocytes, thereby ameliorating liver steatosis.

Modulation of Lipid Metabolism by Trans-Anethole in Hepatocytes

Non-alcoholic fatty liver disease is caused by excessive lipid accumulation in hepatocytes. Although trans-anethole (TAO) affects hypoglycemia and has anti-immune activity and anti-obesity effects, its role in non-alcoholic fatty liver disease remains unknown. This study aimed to evaluate the effects of TAO on cellular senescence, lipid metabolism, and reinforcement of microenvironments in HepG2 cells. To analyze the lipid metabolic activity of TAO, PCR analysis, flow-cytometry, and Oil Red O staining were performed, and mitochondrial membrane potential (MMP) and cellular senescence kits were used for assessing the suppression of cellular senescence. At 2000 μg/mL TAO, the cellular viability was approximately 99%, and cell senescence decreased dose-dependently. In the results for MMP, activity increased with concentration. The levels of lipolytic genes, CPT2, ACADS, and HSL, strongly increased over 3 days and the levels of lipogenic genes, ACC1 and GPAT, were downregulated on the first day at 1000 μg/mL TAO. Consequently, it was found that TAO affects the suppression of cellular senescence, activation of lipid metabolism, and reinforcement of the microenvironment in HepG2 cells, and can be added as a useful component to functional foods to prevent fatty liver disease and cellular senescence, as well as increase the immunoactivity of the liver.